Magic Answer Ball

Ask MIEO a yes-or-no question, like “Will it rain tomorrow?” or “Should we have pizza tonight?”, then press its L button. MIEO plays a thinking animation while it ponders, and then it answers: a smile and a happy sound for yes, a crying face and a sad sound for no, or a shy face and a chirp for maybe. Of course MIEO doesn't really know. It picks an answer at random, just like a fortune-telling ball. Along the way you'll learn how a program keeps a number in a variable and chooses what to do with it.

• Keeping a random number in a variable
• Checking a variable with “=” to choose an answer
• Putting one “if … else” inside another to pick one of three
• Using an animation that finishes before the program carries on

• Mieo board
• Battery
• 3D-printed mountings
• Screws and screwdriver
• A USB cable, or Bluetooth on your computer
• The Robolab app (free)

1. Fit the battery into its 3D-printed mounting on the back of the Mieo board and fix it in place with the screws.
2. Connect the battery to the board as shown in your kit's build guide, then switch MIEO on.
3. Connect MIEO to your computer with a USB cable, or turn on Bluetooth on your computer so Robolab can find it.

Want MIEO Bot to guide you?

Robolab's built-in tutor has a lesson on the same idea, “Magic Answer Ball”. Open MIEO Bot in Robolab, pick Maker, then Mieo, and it shows you the blocks one at a time and checks your work as you go.

About MIEO Bot's lessons

1. Open Robolab, choose Mieo, connect and set the switch at the top right to Arena. In Variables, make a variable called answer.
2. Start with “when green flag clicked” and “show neutral”, then add a “forever” loop with “if … then” inside. Its condition is “is button L pressed?”.
3. Inside the if, add “show think animation until done”, then “set answer to” with “pick random 1 to 3” in its slot. 1 means yes, 2 means no and 3 means maybe.
4. Add “if … else” with “answer = 1”. For yes, put “show happy” and “play sound happy until done” in its top part.
5. In its else part, add another “if … else” with “answer = 2”. For no: “show cry” and “play sound sad until done”. For maybe, in the last else: “show shy” and “play sound chirp until done”.
6. After the answers, still inside the first if, add “wait 2 seconds” and “show neutral”, ready for the next question.
7. Click the green flag, ask a question and press L.

Arena mode: the program runs on your computer and talks to MIEO live over USB or Bluetooth, so keep MIEO switched on and connected.

when green flag clicked
show [neutral v]
forever
  if <is button [L v] pressed?> then
    show [think v] animation until done
    set [answer v] to (pick random (1) to (3))
    if <(answer) = (1)> then
      show [happy v]
      play sound [happy v] until done
    else
      if <(answer) = (2)> then
        show [cry v]
        play sound [sad v] until done
      else
        show [shy v]
        play sound [chirp v] until done
      end
    end
    wait (2) seconds
    show [neutral v]
  end
end

MIEO shows a calm face. Ask a question and press L: the thinking animation plays, then MIEO answers with a smile and a happy sound, a crying face and a sad sound, or a shy face and a chirp. Two seconds later it's calm again. Press L a few more times: the answers change at random.

If it doesn't work

• It always gives the same answer? Check that “pick random 1 to 3” is inside “set answer to”, and that each check uses the answer variable.
• It never says maybe? The maybe face goes in the very last else part, under the check for 2.
• Nothing happens when you press L? Check that MIEO is connected, the switch says Arena, and you clicked the green flag.

1. Easy: choose your own faces and sounds for each answer, such as heart for yes.
2. Medium: add a fourth answer, “ask me later”, with “pick random 1 to 4” and one more check.
3. Hard: make yes come up more often than no: pick a number from 1 to 10, and answer yes for anything up to 6.